The field of the present invention relates generally to optical code readers using Scheimpflug optics.
Optical code systems, including for example bar code systems, have come into wide use for marking a great variety of objects for automatic reading. Optical codes are used commercially in many applications, including the identification of retail products at the point of sale, control of inventories, and package identification.
Optical codes include, but are not limited to, a series of light and dark areas of varying widths and heights. The simplest of optical codes are often commonly referred to as one-dimensional (hereinafter 1D) and two-dimensional (hereinafter 2D) bar codes. However, other configurations of light and dark areas may also represent optical codes. An example of such a configuration may be symbolic codes, such as a light and dark area configured in the shape of a lightning bolt to represent electricity. Light and dark areas configured in the shape of alphanumeric text may also be read as an optical code.
Most conventional optical code readers suffer from shallow Depth of Field (DOF). Due to the shallow DOF, optical codes only remain in focus over a narrow range of distances. In addition, most conventional optical code readers have difficulty reading optical codes that are oriented in random directions.
The present invention is directed to systems and methods for increasing the DOF of an optical code reader. A preferred configuration comprises an optical reader having Scheimpflug optics to increase the DOF while retaining adequate light levels for efficient optical code signal processing. The optical code reader having Scheimpflug optics further has the capability to read an optical code at a random orientation while providing a preferred DOF for accurate reading. In a preferred embodiment, the optical code reader comprises a plurality of image sensor arrays mounted at an angle in accordance with the Scheimpflug principle to provide a preferred DOF. Each of the plurality of image sensing arrays is oriented in a different direction to provide a plurality of raster patterns. The plurality of raster patterns taken together as one provides a sample-scan line pattern. By creating a complex sample-scan line pattern, omni-directional optical code reading is allowed.
In one preferred configuration, the optical code reader has a rotatable image sensor array in an optical code reader. The rotation of the image sensor array is synchronized with timing of the scan of different raster patterns such that a sample-scan line pattern is created.
In another configuration, the optical code reader has a singular image sensor array set at an angle in accordance with the Scheimpflug principle. This configuration has an optical device provided to rotate the rays of light, which make up an image of the optical code onto the image sensor array. The rotation of the optical device is synchronized with the timing of the scan of different raster patterns such that a sample-scan pattern is created.
These as well as other configurations of the present invention will be apparent to those of skill in the art upon inspection of this specification and the drawings herein.